SHA-256 vs MD5: Which Hashing Algorithm Should You Use?

Hashing is fundamental to security — password storage, file verification, digital signatures, and data integrity checks all rely on it. But not all hash functions are equal. MD5 is fast but broken for security; SHA-256 is the modern standard.

What Is a Cryptographic Hash?

A hash function takes input data of any length and produces a fixed-length output (the "digest"). Good hash functions have three properties:

• One-way: You cannot reverse a hash to get the original input
• Deterministic: Same input always produces the same hash
• Avalanche effect: Changing one bit of input completely changes the output

MD5: Fast but Broken

MD5 produces a 128-bit (32 hex character) digest. It's extremely fast, which is why it's still used for non-security purposes like file checksums and cache keys. But MD5 is cryptographically broken — researchers have demonstrated collision attacks (two different inputs producing the same hash) since 2004. Never use MD5 for password hashing or digital signatures.

SHA-256: The Modern Standard

SHA-256 (part of the SHA-2 family) produces a 256-bit (64 hex character) digest. It's used by TLS certificates, Bitcoin, code-signing, and government systems. No practical collision attack exists. Use SHA-256 for any security-critical hashing.

For Passwords: Use bcrypt or Argon2

Neither MD5 nor SHA-256 should be used to hash passwords directly — they're too fast. Password hashing needs to be intentionally slow to prevent brute-force attacks. Use bcrypt, scrypt, or Argon2 for password storage. They include salting and are designed to be computationally expensive.

Generate and verify hashes with our Hash Generator tool.